Gloom for the Ecstatic
Maartje M. L. de Win, Gerry Jager, Jan Booij, Liesbeth Reneman, Thelma Schilt, Cristina Lavini, Sílvia D. Olabarriaga, Gerard J. den Heeten and Wim van den Brink, "Sustained effects of ecstasy on the human brain: a prospective neuroimaging study in novel users", in Brain, Vol. 131, No. 11, November 2008, pp. 2936–2945.
Although we do not know yet whether these effects are reversible or not, we cannot exclude that ecstasy even in low doses is neurotoxic to the brain.